The present invention relates generally to round balers with net wrapping capabilities and more particularly to a manually actuated net wrapping mechanism for a round baler that relies primarily on mechanical components in the net wrapping mechanism to provide operator feedback on the wrapping process.
In the crop packaging industry, generally a smaller part of the cattle/dairy industry, round balers have become quite prevalent for their capability of producing a conveniently sized cylindrical bale, very often automatically wrapped with a sheeting material such as net or film. Prior art round balers generally have a bale-forming chamber defined by an apron comprising an array of side-by-side belts, transverse slats trained on chains, a plurality of rolls or a combination of these various elements, e.g., rolls and belts. Crop material, such as hay, is picked up from the ground as the baler travels across the field, and is fed into a fixed or expandable chamber where it is rolled up to form a compact cylindrical hay package. While still inside the bale-forming chamber in its compacted form, the outer surface of the package is wrapped with twine or other wrapping material, such as film or net, prior to ejection of the wrapped bale from the chamber onto the ground for subsequent handling.
U.S. Pat. No. 5,289,672 and U.S. Pat. No. 4,956,968, issued to Underhill, disclose prior art round balers having a wrapping apparatus of the general nature described above. In this particular type of baler an expandable chamber is defined by a pair of fixed sidewalls, and a plurality of side-by-side belts cooperating with a series of transverse rolls, mounted between a pair of pivotally mounted arms. This arrangement of rolls and arms is commonly referred to as a sledge assembly. The chamber includes an inlet opening in the front through which crop material is fed. Also included is a pair of take up arms pivotally mounted on the main frame, between which arms a pair of guide rolls are journalled. A biasing force on the take up arms urges the outer surfaces of the guide rolls against the belts to maintain tension and thereby prevent slack from occurring in the belts during expansion and contraction of the chamber. Density of the bale can be affected by varying the force on the take up arms.
The present invention relates to a wrapping system for a round baler in which a cylindrical package of crop material (bale) is formed in a fixed or expanding chamber wherein one or more transverse forming rollers are employed. It is not uncommon in prior art round balers having this general configuration to feed the wrapping material between a pair of the transverse rollers. A supply of wrapping material is dispensed from a supply area in the baler housing into the bale forming chamber through the space between two of the transverse rolls whereupon the wrapping material comes into contact with and adheres to the outer surface of the bale as it is rotated by the rolls. The net wrapping system includes a net insertion assembly which is inserted into the space between the two transverse rolls while gripping a free end of the wrapping material to feed the end of the wrapping material into the bale forming chamber and initiate the wrapping process. The protruding portion of the insertion assembly is commonly referred to as the duckbill. Once the net is wrapped around the outer circumference of the bale, the wrapping material is severed from the supply by a knife in the wrapping apparatus.
In larger round balers, the wrapping systems generally employ a significant number of electronic components for sensing the position of various portions of the mechanism and for controlling the application of the wrapping material to the moving bale, specifically positioning of the duckbill. These controls automate the baling and bale wrapping processes to reduce the demands on the operator. An exemplar electronically controlled wrapping mechanism is disclosed in U.S. Pat. No. 4,674,403 by Bryant et al. and features an electronic control circuit for managing the baling and wrapping process. For smaller farming operations in which lower equipment cost is generally preferred over a greater degree of automation, a less complex control system or a manually actuated system is desirable.
It would be desirable to provide a mechanism for applying a wrapper to a bale in a baler that reduces the reliance on electrical control components, replacing some or all of those devices with functionally equivalent mechanical devices to enable the status of wrapping process to be monitored by an operator so that process steps may be manually initiated. Still more desirable would be an apparatus that is easily incorporated into existing round baler designs with minimal alteration of the bale wrapping mechanism.